diff --git a/src/lnf.rs b/src/lnf.rs
index 8acd421..f8b3ad9 100644
--- a/src/lnf.rs
+++ b/src/lnf.rs
@@ -41,7 +41,7 @@ impl TypeTerm {
                 new_ladder.push( TypeTerm::App(vec![]) );
 
                 for arg in args_iter {
-                    match arg.clone() {
+                    match arg.normalize() {
                         TypeTerm::Ladder(rungs) => {
                             // duplicate last element for each rung
                             let l = new_ladder.len();
diff --git a/src/test/lnf.rs b/src/test/lnf.rs
index 486c0d6..1c81a55 100644
--- a/src/test/lnf.rs
+++ b/src/test/lnf.rs
@@ -43,5 +43,15 @@ fn test_normalize() {
         dict.parse("<Seq <Digit 10>~Char>").expect("parse error").normalize(),
         dict.parse("<Seq <Digit 10>>~<Seq Char>").expect("parse errror"),
     );
+
+
+    assert_eq!(
+        dict.parse("<A <B C~D~E> F~G H H>").expect("parse error").normalize(),
+        dict.parse("<A <B C> F H H>
+                   ~<A <B D> F H H>
+                   ~<A <B E> F H H>
+                   ~<A <B E> G H H>").expect("parse errror"),
+    );
+
 }